The objectives of the project are to continue to recall patients who have had several dental restorative materials placed under controlled operative conditions. These materials are compared for marginal integrity, durability, recurrent decay and color stability. The study compares composite resins with silicate restorations in the anterior teeth, and composites with silver amalgam as two-surface restorations, in the posterior teeth. The most recent clinical study compares silver amalgam restorations placed under two conditions: first, placing an amalgam adjacent to a previously placed gold casting restoration, and the second in the reverse order. The placement of dissimilar metals adjacent to each other has been thought to produce corrosion of amalgam. The manifestation of corrosion is shown as a black, disfiguration of the amalgam. Goals for the current year are to continue the recalling of patients for the purpose of recording changes that are seen in the control teeth as well as the teeth restored with various materials. Laboratory testing will continue as before, attempting to predict and correlate the clinical performance of many materials and techniques.